1. Field of the Invention
The present invention relates to a vehicle air-conditioning system in a conventional vehicle which controls a seat air-conditioning unit so as to reduce the amount of fuel consumption at the time the vehicle is stopped etc.
2. Description of the Related Art
Due to the rising need for conserving energy, the drop in fuel economy due to air-conditioner use at the time of idling has been surfacing as an issue. To counter the drop in fuel economy at the time of idling, raising the evaporator temperature etc. may be considered as countermeasures, but simply raising the evaporator temperature of the air-conditioning system detracts from the passengers' feeling of comfort, so is not preferable. Note that, general air-conditioning systems are described in detail in Japanese Unexamined Patent Publication No. 2006-76398, Automotive Air Conditioning, Tokyo Denki University Press, Kenichi Fujiwara et al., Sep. 20, 2009, pp. 88 to 94, etc.
As related art to deal with this issue, Japanese Unexamined Patent Publication No. 2000-142095 may be mentioned. In this art, hybrid cars or cars mounting economic running systems (cars with idling stop systems) are adjusted in seat air-conditioning ability and compartment air-conditioning ability so as to increase the engine stop time at times other than ordinary operation and thereby save energy.
As opposed to this, in conventional vehicles, the engines have no automatic stop, so art such as in Japanese Unexamined Patent Publication No. 2000-142095 cannot be used. In conventional vehicles, to maintain the cooling ability of the vehicle air-conditioner while the engine is stopped (and while it is idling), it is necessary to operate the compressor of the refrigeration cycle during that period. Usually the engine turning force is used to drive the rotation of the compressor, so to operate the compressor at the time of idling, it is necessary to raise the engine speed so that the engine does not stop (“idling up control”). As a result, the problem arises that when the air-conditioning is on, compared with when the air-conditioning is off, the amount of fuel consumption ends up increasing.